Nowadays control units, sensors, actuators are increasingly connected to one another, or networked, wirelessly in order to ensure the greatest possible flexibility. In this situation it is also simpler to carry out maintenance on the units or sensors because for example in the case of a malfunction there is no need to open any cable ducts etc. but merely the unit directly. Open protocols such as IEEE 802.11 WLAN, IEEE 802.15.4, Bluetooth, ZigBee or also Wireless HART are normally used in order to connect the aforementioned control units, sensors, etc. In order where possible to avoid any manipulation of the sensors or instructions to the control units during the wireless connection the communication from the control unit or sensor is cryptographically encoded by the corresponding point interface, for example through a WLAN connection using TKIP or CCMP, or in the case of 802.15.4 using AES-CCM. In order to connect a control unit, a sensor or similar to a wireless station and to establish an encrypted connection the control unit, the sensor or the wireless communication device in general must be configured such that the appropriate encryption is used, in other words for example that a cryptographic key is set up. The setup of such a key is also referred to as bootstrapping or pairing.
It is known from US 2006/282885 that an administrator unit of a wireless unit to be configured wirelessly provides a proof of authority. The wireless unit is configured by the administrator unit using the proof of authority provided by the administrator unit.
It is furthermore known to conduct an in-band communication during a weakly protected phase. For this purpose, the corresponding wireless communication unit to be set up does however require special modified transfer methods. Finally, it is known to conduct a pairing secured by an out-of-band channel, such as for example human interaction (in other words entering or checking a PIN, etc.).
Disadvantageous in this case is the fact that the aforementioned methods require a high degree of effort and are complicated in design, particularly when used in the industrial sector because a large number of wireless communication devices are set up there. In this situation it is at the same time necessary that the pairing takes place in protected or secured fashion because the security configuration parameters are set up in the process.